ABSTRACT: Multi–method geo- and thermochronological data obtained for Palaeo- and Mesoproterozoic granitoids traversing the main structural architecture of the eastern Musgrave Province within South Australia reveal multiphase cooling histories.
Apatite U-Pb dating on six samples yield consistent ages of ~ 1075–1025 Ma, suggesting a thermal reset coinciding with mantle-derived magmatism of the greater Warakurna Large Igneous Province (~ 1080–1040 Ma).
Temperature-dependent He release from zircon is not consistent with thermally activated volume diffusion from a single domain.
Instead, in most samples apparent He diffusivity decreases and activation energy () increases as cycled step-heating experiments proceed.
First, it dramatically increases sample throughput. Measuring the U and Th content of zircon by isotope dilution requires dissolution in hydrofluoric acid at high temperature and pressure using a Parr bomb for up to 48 hours.
This radioactive decay forms the basis of the U-Th-Pb and U-Th-He methods of geochronology, each of which have different geological significance.